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Like virtually all airports around the world, the terminal
building at Tweed-New Haven airport had a problem: REVERBERATION.
As a result, the public address system used to page
people and make flight announcements was virtually unintelligible,
causing confusion and inconvenience for employees and
travelers alike.
 While
problems of this type abound in public buildings, this
case was especially severe and with good reason. The
229,000 cubic foot space was designed and initially
used as an airplane hangar. Never intended as an acoustically
friendly space, it had a number of properties that exacerbated
reverberation – such as reflective glass block
walls, vinyl covered concrete flooring and a steel ceiling.
To make matters worse, these hard surfaces were parallel
to each other, which allowed sound to bounce freely
from wall to wall and ceiling to floor with minimal
diffusion.
According to Susan Lewis, Airport Manager, the noise
problem did not go unnoticed. “I received
complaints from the airlines, rental car agencies, food
concessionaires and passengers”, she says.
“No one could understand the announcements.”
The first step in the acoustical treatment was to measure
the amount of reverberation in the terminal. This involved
conducting an RT60 test at 2:00 AM when the facility
was virtually empty and at it’s quietest. The
basic reverberation test was conducted using a hand-held
decibel meter to measure the amount of time it takes
for a loud noise to decay by 60 decibels. Simply simply
popping a 20” balloon with a pin created the sound.
According to architectural acoustic design guidelines,
the ideal reverberation time for speech to be totally
intelligible in a room of this volume would be 1.5 seconds.
However, in this case it was 5 seconds, no wonder the
place echoed as badly as it did.
 To
solve the problem Sonex™
Valueline baffles were recommended for suspension
from the ceiling. Baffles provide significantly better
sound absorption than treatments that attach direct
to the face of walls and ceilings. The reason is that
a free hanging baffle can absorb sound on all sides,
rather than on a single surface.
According to the calculations, the job would have required
700 2’x4’ Sonex™
Valueline baffles to bring the reverberation level
to the desired 1.5 seconds. This goal, however, proved
to be unrealistic. Not only were there budget considerations,
but also the ceiling space was simply not large enough
to handle that quantity of hanging baffles.
The reverberation target was readjusted to 2.0 seconds
as an economical and practical compromise. To reach
this goal, it was determined that the space needed an
octal of 3,500 sabins of sound absorption. Since each
2’x4’x2” Sonex™
Valueline baffle absorbs approximately 10 sabins,
so 350 baffles were recommended to be installed.
The excellent sound absorption capabilities and affordability
are two of the main reasons why Sonex™
Valueline was a good choice for this application.
Other reasons include the fact that Sonex™
Valueline baffles are made of a Willtec foam material,
which is class A fire rated building material with low
flame spread and smoke production. This is always an
important consideration – especially in public
buildings. In addition, the subtle convolutions on the
surface of the baffles make them aesthetically eye pleasing.
Upon completion of the project a follow up reverberation
test was taken to determine the final effectiveness
of the solution. The Sonex™
baffles lowered the reverberation time down to 1.8
seconds, which was a full 10% better than the design
target. The true measurement of the solution’s
effectiveness, however, is how well the people who work
at the airport receive it. These results were equally
pleasing. “Since the Sonex™
Valueline baffles were installed, there have been
many positive reactions,” Lewis says. “People
have commented on how nice it is to finally be able
to here the public address announcements. I’ve
also heard many people say that they think the baffles
enhance the look of the facility, too”.
Lewis also noted that the benefits of the Sonex™
Valueline baffles extend beyond its acoustic and
aesthetic values. “The airport is currently
trying to attract more airlines to the facility. I believe
that the improved sound environment will make the facility
more customer friendly and attractive to both airlines
and passengers”.
Tweed-New Haven is now one of the few municipal airports
in the country where you can actually understand everything
that’s said on the public address system.
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